The present invention relates generally to medical methods, apparatus and systems. More specifically, the invention relates to methods, apparatus and systems for optimizing the progression of a cardiac catheter through the coronary sinus among other venous features by monitoring blood flow.
Placement of cardiac leads in the distal branches of the coronary venous system, the great cardiac vein, or the coronary sinus provides new medical opportunities to place medical devices on the left ventricle with a much lower patient morbidity than direct placement within the ventricle. However, maneuvering devices into the coronary sinus can be a difficult task.
Deploying a pacing lead through the coronary sinus and into the distal venous system is often challenging if not impossible using standard techniques and equipment. In addition, it is often impossible to place the lead in an optimum location, for pacing or sensing cardiac electrical activity, either because there are no vessels in this region or the vasculature is too small or tortuous and therefore hard to find.
There are several reasons which make proper placement of the lead in these challenging locations difficult. These include difficulty in locating and maneuvering devices into the coronary sinus and beyond, partial obstruction of the vasculature, and unusually shaped bifurcations in the vasculature.
Prior efforts to resolve such problems included the use of stiffer guidewires, with an attended risk to the vessel walls through which the guidewire and lead are inserted. While stiffer guidewires offer additional support, they may impede advancement due to their stiffness or inability to navigate more tortuous anatomy. Leads have also been developed, such as those reported by Westlund et al (U.S. patent application Ser. No. 10/081,436 filed Feb. 20, 2002), which have sections of various stiffness, temporary locking means, and other features to expedite coronary sinus access.
Other approaches to improving coronary sinus access are an effort to detect and analyze electrical events to determine the electrodes' position, such as reported by Yu et al (U.S. patent application Ser. No. 10/729,301 file Dec. 5, 2003).
Mechanical, electrical, and fluoroscopy approaches to placement of cardiac devices into the coronary sinus and beyond have been helpful, but the need remains for a practical approach to more simply maneuver devices based on immediate, real-time local sensing. Such an advancement in the medical device arts would allow an important clinical advantage and, in some cases, availability of this important clinical approach for the first time.